1. Field of the Invention
The present invention is related to light emitting diode (LED) control, especially to the method and system for controlling LED with power line carrier (PLC).
2. Description of Related Art
Nowadays, people have created various electronic devices which make the life much more convenient. But with more and more electronic devices being used, the transmission line needed also increases accordingly. Therefore, many technologies have been explored so as to reduce the amount of usage for transmission lines, such as wireless transmission technologies, automation technologies, or power line carrier (PLC) technologies, etc.
Therein the power line carrier or power line communication technologies are systems for carrying data on conductors that are also used for electric power transmission. Electric power is transmitted over high voltage power transmission lines, distributed over medium voltage, and used inside buildings at lower voltages. Power line carrier technologies can be applied at each stage of high, medium, or low voltage.
All power line carrier systems operate by impressing a modulated carrier signal on the wiring system. Different types of power line carrier technologies use different frequency bands, depending on the signal transmission characteristics of the power wire being used. Since the power wire system was originally intended for transmission of alternating current power, the power wire circuits have been designed only with a limited ability to carry power and data in higher frequencies, and various propagation problems act as limiting factors for each type of power line carrier technologies.
Light emitting diode (LED) is a diode that emits light when an electric current is applied in the forward direction of the device. LEDs are widely used as indicator lights on electronic devices and increasingly in higher power applications such as flashlights and area lighting. An LED is usually a small area (less than 1 mm2) light source, often with optics added directly on top of the chip to shape its radiation pattern and assist in reflection. The color of the emitted light depends on the composition and condition of the material used, and can be infrared, visible, or ultraviolet. In addition to lighting, interesting applications include using Ultraviolet-LED for sterilization and disinfection, and as a grow light to enhance photosynthesis in plants.
With more and more LEDs being used, the importance and need of LED control are also increasing. Generally, many signal transmission lines are required for controlling LEDs that are numerous in number, and the costs and resources consumption of setting up numerous signal transmission line wirings are relatively high. Moreover, the difficulty of setting up or removing sets of LED wirings increases due to these wirings.